The present disclosure pertains to a composition that controls the chemical release of functionally active components from a previously inactive and modified state. In particular, the present disclosure pertains to a composition that gradually or rapidly releases active chemical components upon the occurrence of specific environmental stimuli. The composition can be used in bandages, hygiene products, health care products and skin-contacting beauty products, as well as in consumer product applications. The present disclosure also relates to such bandages, hygiene products, health care products, beauty products and consumer products incorporating such chemistry.
A large number of functionally active chemicals are known for use with personal care and beauty products, hygiene products, health care related products, and skin-contacting products. For example, such actives include antimicrobial or antibacterial agents, antioxidant agents, antiseptic-type agents, skin-repairing agents, and fragrances. Unfortunately, many of these functionally-active chemicals are not stable or do not have ideal properties under various environmental conditions. For example, if such actives include volatile components such as those found in fragrances, they can dissipate into the surrounding environment upon exposure to air and humidity conditions. Therefore, such chemicals can demonstrate short shelf lives when in use, and can present serious packaging/storage concerns. As a result, costly packaging can be necessary for products incorporating such chemicals. This instability creates a significant limitation on the wide adoption of the potentially useful chemistry and limits the long-term efficacy of products incorporating such chemistry. Further, processing challenges such as elevated temperatures can exist, and, as a result, can present a need to limit exposure to environmental stimuli during manufacture.
Additional challenges presented by the use of such active chemicals include the difficulties involved with gradually controlling the release of such active chemicals, as well as the potential side effects and costs resulting from use of chemically degraded products. Other actives, such as antioxidants, are also often not stable when exposed to ambient conditions, such as the air of a user's pantry or storage closets. Antioxidants can readily be oxidized by oxygen in the air. Some skin-repairing chemicals are also not stable when exposed to the surrounding environment. For example, the skin-repairing agent retinol is not stable under ambient conditions without protection from the environment. In fact, it can become a skin irritant when its concentration is relatively high. Currently no proactive technology has emerged to be very effective to achieve both property modification and at the same time release-on-demand under mild conditions. For example, anti-oxidants such as vitamin C and vitamin A are often stabilized through the ester forms which are hydrolyzed into the active forms through enzymes when digested into bodies. In many cases, a large portion of the actives are wasted because they are not hydrolyzed and released to the desired locations. A need therefore exists for a versatile composition that effectively stabilizes functional chemical actives, and releases such actives upon demand, at a desirable rate and profile.
Attempts have been made to overcome the stability and storage limitations presented by such actives. For example, some have suggested stabilizing retinol by encapsulating it in pH-sensitive polymers and then releasing it at a later time by changing the solubility of the encapsulating matrix through a pH change. The encapsulated retinol still suffers significant degradation, presumably from oxidation. Others have suggested converting retinol into an ester as a proactive (a precursor to the retinol active), and then at a later time converting the ester into the active form by use of enzymes present in a user's body after delivery through a user's skin. With such methodology, however, only a small portion of the ester is used effectively by the skin layer and a majority of the esters are wasted by the system. Such a system can also actually lead to side effects when too much retinol ester is used to achieve effective dosages on the skin. Therefore, a need still exists for delivery compositions for skin-repair actives.
In connection with the delivery of fragrances (such as in connection with personal care absorbent products), it has been suggested to encapsulate fragrances in polymeric matrices for stabilization and delivery benefits. Even with such encapsulation technology, however, there is a further need for fragrance encapsulation technology that offers effective protection for such volatiles as well as a controlled release. Existing encapsulation chemistries for consumer products often leak or release prematurely. A continuing need exists for a material composition that both provides stability for unstable actives, and that provides for release of actives in a controlled manner.